Miner&#39;s safety lamp indicating the amount of fire damp in the air



Jan. 21, 1930. sc 1,744,416

MINERS SAFETY LAMP INDICATING THE AMOUNT OF FIRE DAMP IN THE AIR Filed Aug. 10, 1927 Patented Jan. 21, 1930 ATE GEORGES SCI-IAULY, OF IIANTES, FRANCE MINER/S SAFETY LAMP INDICATING- THE AIKGUNI OF FIRE DAMP IN THE AIR Application filed August 10, 1827, Serial No. 212,122, and in France August 16, 1926.

My invention is based upon the observation of a flame of a miners safety lamp which is more or less elongated according as the amount of fire-damp in the surrounding air increases, and whose temperature increases accordingly.

I cause these two factors to act concurrentlv upon a suitable thermo-electric couple, variations in current are measured by a milli- 19 ampere meter carrying a scale graduated in percentages of fire clamp.

The invention is further adapted to produce distant signals when the amount of firedamp becomes dangerous at a given point,

' and the variations in the thermo-electric current from the said couple are caused to act at a distance over a circuit containing a sui able signal device of an optical, magnetic, electric, acoustic or like nature.

The thermo-electric couple which offers the best results is composed of nickel and chromium.

The thermo-electric device may be placed above the lamp, but I prefer to dispose it in the interior of the lamp and above the flame; it may comprise a single element or a plurality of elements, connected in series or in parallel.

The thermoelectric device is herein disposed on the axis of the flame, and the hooked-shaped thermo-electric joint is directly exposed to the action of the flame, the remainder of the device as well as the conductors being covered with asbestos.

The conductors of the thermoelectric device are connected with a pair of insulated metallic rings placed upon the exterior of the lamp; however one ring may be replaced by the metal body of the lamp, or the said ring may be riveted to the lamp, and the latter may also be connected with one end of the thermoelectric device in order to reduce the temperature of the latter.

The connection between the end or ends of the thermoelectric device and the insulated ring or rings is assured by insulated conductors disposed in a transverse tube soldered to themetal body of the lamp, so as not to interefere with the functioning of the lamp and the circulation of oil in the wick.

The appended drawings show by way of example a miners safety lamp according to the invention.

Fig. 1 is an elevational View of the apparatus, partly in section.

Fig. 2 is a plan-section view.

Fig. 3 is a detail view showing the operation of the lamp.

As observed in the drawings, the safety lamp 1 of the Davy or other type is provided immediately above the flame 2, and in the axial position, with a hook shaped joint 3 of a nickel-chromium thermoelectric couple 1 whose rigid conducting supports 56 are covered with asbestos; said supports are mounted in the electric terminal pieces 89 which are insulated from the main body and are connected by the insulated conductors 1011, passing through the tubes 1213 soldered to the main body, with the conducting rings 1415 which are insulated from the lamp by the fibre rings 16-17 and carry the outer terminals 18-19; the latter are connected by the wires 2021 with the terminals 2223 of a milli-ampere meter 24.

Fig. 3 shows the forms assumed by the flame according to the amount of fire-damp in the air, and also the corresponding graduated scale on the milli-ampere meter.

It should be noted that the voltage of the current from the thermoelectric couple is on the order of 1/20 volt, so that it will not produce a dangerous spark at the exterior; also, certain joints such as platinum and iridiumrhodium, iron and melchior metal, and silverbismuth cannot be employed in this apparatus.

I claim:

1. In combination with a miners lamp, of a circuit including an indicator of electromotive force and a nichrome thermo-couple supported on said lamp and terminating directly above the wick of said lamp and spaced therefrom.

2. In combination with a miners lamp, of a nichrome thermo-couple supported on spaced contacts on said lamp, the free ends of said couple being soldered together and terminating directly above the wick of said lamp and spaced therefrom, and a milliammeter connected with said thermo-couple. 3. In combination With a miners lamp, of a nichrome thermo-icouple supported on spaced contacts on said lamp, said couple elements extending upwardly and being bent over and down and soldered at their free ends, said ends being positioned directly above the Wick of said lamp adapted to be afi'ected by the flame, conductor conduits eX- tending from said contacts on said lamp through the same and terminating on the side thereof insulated conductors connected to said contacts and extending through said conduits, and a milliammeter connected With the free ends of said conductors.

In testimony whereof I aflix my signature. v

GEORGES SOHAULY. 

